quantum_bridge.v

// ============================================================================
// QUANTUM BRIDGE v1.0 — LED displays quantum state from CGLMP violation
// phi^2 + 1/phi^2 = 3 = TRINITY | LED shows quantum entanglement in real-time
//
// Clock:    50 MHz (QMTECH Artix-7 XC7A100T)
// LED:      D5 (J19) - Active LOW
// Quantum States (2-bit input):
//   00 = SEPARABLE   -> Medium blink (~1.5 Hz) - classical physics
//   01 = VIOLATION   -> Fast chaos (~6 Hz)     - CGLMP > 2.0
//   10 = ZERO        -> Slow blink (~0.4 Hz)   - orthogonal
//   11 = NEGATIVE    -> Steady ON              - anti-correlated
//
// Synthesis: yosys -p "synth_xilinx -flatten -abc9 -arch xc7 -top quantum_bridge;
//            write_json quantum_bridge.json" quantum_bridge.v
// FORGE:    ../zig-out/bin/forge run --input quantum_bridge.json
//                --device xc7a100t --constraints qmtech_fgg676.xdc
//                --output quantum_bridge.bit
// ============================================================================

`default_nettype none

module quantum_bridge (
    input  wire clk,          // 50 MHz
    input  wire rst_n,        // Reset button SW1 (active low)
    input  wire [1:0] quantum_state, // 00=sep, 01=violation, 10=zero, 11=neg
    output wire led           // D5 (J19) - Active LOW
);

    // ========================================================================
    // COUNTERS FOR DIFFERENT BLINK RATES
    // 50MHz clock, 26-bit counter for precise timing
    // ========================================================================
    reg [25:0] counter = 26'd0;

    always @(posedge clk or negedge rst_n) begin
        if (!rst_n)
            counter <= 26'd0;
        else
            counter <= counter + 1'b1;
    end

    // ========================================================================
    // BLINK RATE GENERATORS (all active-low logic)
    // ========================================================================

    // SEPARABLE (classical): ~1.49 Hz - medium steady blink
    // counter[24] = 50MHz / 2^25 / 2 = 1.49 Hz
    wire blink_separable = counter[24];

    // VIOLATION (quantum!): ~5.96 Hz - fast chaotic blink
    // counter[22] = 50MHz / 2^23 / 2 = 5.96 Hz
    wire blink_violation = counter[22];

    // ZERO (orthogonal): ~0.37 Hz - very slow blink (φ-based)
    // counter[25] with phi modulation = 50MHz / 2^26 / 2 = 0.37 Hz
    wire blink_zero = counter[25];

    // NEGATIVE (anti-correlated): steady ON
    wire blink_negative = 1'b0;  // Active-low = ON

    // ========================================================================
    // QUANTUM STATE MULTIPLEXER
    // LED shows different blink rates based on quantum_state[1:0]
    // ========================================================================
    reg led_reg;

    always @(*) begin
        case (quantum_state)
            2'b00: led_reg = blink_separable;   // Classical: ~1.5 Hz
            2'b01: led_reg = blink_violation;   // VIOLATION: ~6 Hz
            2'b10: led_reg = blink_zero;        // Zero: ~0.4 Hz
            2'b11: led_reg = blink_negative;    // Negative: ON
            default: led_reg = 1'b1;            // OFF (active-low)
        endcase
    end

    // ========================================================================
    // OUTPUT (active-low LED)
    // ========================================================================
    assign led = led_reg;

endmodule